The present invention relates to a method of obtaining a pseudofiltering effect in the process of data accumulation.
Various filters are used in signal or information processing applications. Conventional filters are classified into two major categories: real-time filter and digital filter. The real-time filter takes the form of an electronic part or circuit that uses a resistor, a capacitor, etc. The digital filter digitizes its incoming signal and stores it, and then performs an arithmetic operation on the stored data to remove unwanted frequency components.
Real-time filters are extensively used in various apparatus as an important component. However, their characteristics offer only a limited degree of freedom, and it is not easy to modify the characteristics. Further, it is difficult to independently set the two filter characteristics, i.e., amplitude and phase. In contrast, digital filter have some advantages that real-time filters cannot offer. For example, digital filters have a function which can be set at will, and permit various filter functions to be worked upon the same data in turn by trial and error. However, it is necessary for digital filters to accept a large volume of raw data and place it in memory once. In addition, programs must be prepared for complicated arithmetic operations. In this way, use of a digital filter needs complex and large hardware. The prior art relating to filtering as applied in the field of nuclear magnetic resonance spectrometry is described in U.S. Pat. No. 3,824,452 and Journal of Magnetic Resonance, 43, 256-281, (1981).